Semirigid tube supporting tie



March 25, 1969 F. w. HOCHMUTH ETAL 3, 3 ,5

SEMIRIGID TUBE SUPPORTING TIE Sheet 0r 2 Filed June 22, 1967 FRANK W. HOCHMUTH JAY H. FREIDAY INVENTORS AGENT United States Patent 3,434,531 SEMIRIGID TUBE SUPPORTING TIE Frank W. Hochmuth, West Simsbury, and Jay H. Frelday,

West Hartford, Conn., assignors to Combustion Engineering, Inc., Windsor, Conn., a corporation of Delaware Filed June 22, 1967, Ser. No. 648,111 Int. Cl. F28f 9/00 US. Cl. 165-67 6 Claims ABSTRACT OF THE DISCLOSURE A tube supporting tie for transversely tying together two closely spaced parallel tubes having a near side and a far side. The tie comprises at least one right-hand S-shaped strap bridging the near side of the one tube and the far side of the other tube, and a left-hand S-shaped strap bridging the near side of the other tube and the far side of the one tube, whereby differential or transverse displacement of the tubes will primarily produce tensional stresses only.

Background of the invention The invention relates generally to fluid heaters of the tubular planel or platen type and more particularly to a tie for transversely supporting these platens on vertical or horizontal supporting tubes.

Superheater heating surface in large steam generators consists frequently of rows of suspended tubular panels or platens spaced across the upper portion of the furnace chamber, with these platens often constructed of vertical, closely spaced parallel tubes. A steam generator of this type is illustrated and described in US. Patent 2,960,390 issued to F. W. Hochmuth on Nov. 15, 1960, wherein the tubular superheater platens are designated 17 and 18. The platens are supported from hanger tubes which are integral parts of the platens and extend through the roof of the furnace to headers which are supported from overhead steel. Being of considerable length and exposed to a high velocity gas stream or other influences such as from sootblowers, these platens are susceptive to vibration or swaying, subjecting the welded connection of the tie uniting the main body of the platen with the hanger tubes to considerable bending and torsional stresses. Because these stresses occur in an atmosphere of high temperature, present tie supports often fail causing frequent and costly shutdown of the steam generator.

Summary of the invention The herein disclosed improved tube tie overcomes the above problems by the use of pairs of S-shaped straps, one right-hand and the other left-hand. These straps are wrapped around adjacent tubes, the outermost tube of the tube panel and the hanger tube, with the ends of the straps welded to opposite sides of the tubes. This construction will provide a semirigid tie with minimum space requirement between tubes. Any bending of the hanger tubes by panel sway will alternately put half of the straps in tension. There will be only negligible or no bending stress or shear stress from platen sway imposed on the tubes or ties, as would be the case with a direct weld or welded ties of conventional design. The strap tie preferably is subdivided into several individual straps to reduce vertical bending stress caused by diiferential thermal expansions between the platen tubes and the hanger tube. Furthermore, the tie material, where not welded to the tubes, is cooled by being in close contact with the surface of the tubes. The tie is without long projecting portions which would be subject to high temperatures and heat damage.

Brief description of the drawings Other advantages of the invention will become apparent from the following description of an illustrative embodiment thereof when taken in conjunction with the accompanying drawings wherein:

FIGURE 1 is a diagrammatic representation of a steam generator and the upper portion of the associated furnace including superheater platens or panels to which the invention can be applied with great benefit;

FIGURE 2 is an enlarged fragmentary view of the tubular platens showing the location where the herein disclosed support is applied;

FIGURE 3 is an enlarged elevational portion of the outermost tubes of the tubular platens and the adjacent hanger tube, and the herein disclosed semirigid supporting tie connecting the platen with the hanger tube; and

FIGURE 4 is a cross section through the tubes and tie when taken on line 4-4 of FIGURE 3.

Description of the preferred embodiment In FIG. 1, 10 denotes the upper part of a furnace chamher, the walls of which are lined with steam generating tubes 11. Burners 12 introduce fuel and air into the furnace chamber for the generation of combustion gases. Adjacent to one side of the chamber 10 is arranged a boiler 14 to which are connected the furnace tubes 11. From the boiler 14 the steam generated is discharged into a heater comprising rows of superheater tube panels 16, 17 and 18 spacedly arranged across the furnace, and through which the steam flows in the order named. The combustion gases pass upwardly across the superheater panels 16, 17 and 18 and across the boiler tubes 14 to an economizer and other heat absorbing surfaces, not shown, before they are discharged into the atmosphere by conventional means.

Directing our attention to FIG. 2, each tube panel 16, 17 and 18 comprises a multiplicity of aligned parallel tubes which are closely spaced or preferably contact each other. The inlet end tubes 20 of tube panel 16 are connected to header 22, while the outlet end tubes 24 form a loop 25 and continue as the inlet tubes or panel 17. The outlet end tubes 26 of panel 17 are again supported by a header 28 from which the steam is conducted by way of pipe 29 to the inlet header 30 and inlet end tubes 32 of panel 18. The outlet end tubes 34 of panel 18 are connected to outlet header 36 from which the steam is conducted to a point of use. Supporting structure is provided including hangers '28, 39, 40, 41 and 42 for supporting headers 22, tubes 24, header 28, header 36 and header 30, respectively, from overhead steel, as shown on FIG. 1.

The improved tie support 50 herein disclosed, and which will now be described in detail, ties together hanger tube 20a and panel tube 16a; hanger tube 24b and panel tube 16b; hanger tube 24a and panel tube 17a; hanger tube 26b and panel tube 17b; hanger tube 34a and panel tube 18a; and hanger tube 32b and panel tube 18b. All the remaining tubes of each panel 16, 17 and 18 are welded together either throughout their full length or at selected locations such as at 52. FIGS. 3 and 4 illustrate, in an enlarged view, the construction of the supporting tie 50 connecting hanger tube 20a with panel tube 16a, and is typical of the remaining supporting ties indicated in FIG. 2. Tie 50 generally comprises one pair or several pairs of 'S-shaped straps. One strap of each pair is called a right-hand strap and is designated 54, and the other strap is called the lefthand strap and is designated 56, although both straps may be identical in form. While the tubes of panel 16 are shown in close contact with each other and are welded at 52, the hanger tube 20a and panel tube 16a are shown at 55 slightly spaced apart to permit straps 54 and 56 to pass therebetween. Straps 54 and 56 are provided with opposite curvatures which conforms snugly to the curvature of tubes 20a and 16a, thereby atfording intimate contact with the tubes and efficient cooling. The ends 54a of strap 54 and 56a of strap 56, and the ends 5412 of strap 54 and 56b of strap 56, are strength welded to tubes 16a and 20a, respectively. Thus a semirigid connection is achieved which upon swaying of the tube panel is subject to tension and only to minor bending and shear stresses. 'In addition, the supporting tie is preferably subdivided into several pairs of strips (three pairs are shown in FIG. 3) which reduces vertical bending stresses caused by differential movement between tubes such as hanger and platen tubes 20a and 16a.

While we have illustrated and described a preferred embodiment of our invention having vertically arranged tubes, the invention can with equal benefit be applied to tube panels composed of horizontally arranged tubes. It is therefore understood that the above description of the invention is merely illustrative and not restrictive and that variations and modifications may be made therein without departing from the spirit and scope of the invention. We therefore do not wish to be limited to the precise details set forth but desire to avail ourselves of such changes as fall within the purview of our invention.

We claim:

1. A tube supporting tie, two closely spaced parallel tubes having a near side and a far side said tubes being transversely tied together by said tube supporting tie, the improvement comprising at least one right-hand S-shaped strap passing between the tubes and shaped to conform to the contour of the tubes, and structurally connecting the near side of the one tube with the far side of the other tube, and at least one left-hand S-shaped strap passing between the tubes and shaped to conform to the contour of the tubes and structurally connecting the far side of the one tube with the near side of the other tube.

2. A tube supporting tie as defined in claim 1 wherein the tie comprises a multiplicity of pairs of narrow straps to reduce bending stresses in the tie due to difierential movement of the tubes.

3. A tube supporting tie in accordance with claim 1 wherein the ends of said right-hand tie and the ends of said left-hand tie are strength welded to said tubes.

4. A tube supporting tie in accordance with claim 3 wherein said one tube constitutes the outermost tube of a first group of parallel tubes, and said other tube constitutes the outermost tube of a second group of parallel tubes.

5. A tube supporting tie in accordance Wdith claim 4 wherein the tubes of said first group and the tubes of said second group are welded together to form a first tube panel r and a second tube panel, respectively.

6. A tube supporting tie in accordance with claim 3 wherein said one tube constitutes the outermost tube of a group of parallel tubes and said other tube constitutes a supporting tube.

References Cited UNITED STATES PATENTS 2,044,797 6/ 1936 Lamont 122476 XR 2,834,324 5/1958 Schoesson 122476 2,914,040 11/ 1959 Rowand 122476 3,001,514 9/1961 Forsrnan 122476 XR 3,055,349 9/1962 Hamilton et al 122-510 3,196,842 7/1965 Huge et al 122510 XR FRED C. MATTERN, JR., Primary Examiner. MANUEL ANTONAKAS, Assistant Examiner.

US. Cl. X.R. 

